*ist D and flash overexposure

[Paul Stenquist]

I recall the messages here about some members experiencing flash 
overexposure with the *ist D. Tonight I was shooting some tabletop 
studio images with monolight strobes and the *ist D. I started with the 
K 50/1.4 and finished a dozen shots or so, exposing at f16 and f22 at 
1/125. I was working kind of close to the ceiling in order to get 
enough distance between lens and subject, so I switched to the M 35/2. 
The camera consistently overexposed by several stops with that lens. I 
checked my exposure again with a flash meter. Again, it indicated in 
the neighborhood of f22. I cranked the monolights down from 1/2 power 
to 1/8 power and got a meter reading of f11. At f22, I was still at 
least a stop over. I went back to shooting with the 50, turned the 
lights back up to 1/2, and my exposures were once again right on at f16 
to f22. After I finished the shoot, I studied the mounts of the two 
lenses. They are identical. I don't know what's going on here. Does 
anyone have a clue?
Paul